1. Field of the Invention
The present invention relates to a display device, or more particularly, to a liquid crystal display device capable of displaying an image formed on a liquid crystal display panel and a display object existent behind the liquid crystal display panel while switching the image and display object.
2. Description of the Related Art
The demand for liquid crystal display devices is growing in the application fields of not only a computer display and a portable cellular phone unit but also a television set because the display device can be thinned and the weight of the display device is limited. Since a liquid crystal display panel does not emit light by itself, a backlight is disposed on the back of the liquid crystal display panel in order to display an image. Light emanating from the backlight is controlled pixel by pixel, whereby an image is formed.
The liquid crystal display device can be applied to various display devices because it can be thinned. For the application to a game display, in addition to an image visualized by a liquid crystal, a specific image is requested to be displayed using the same liquid crystal screen. As a construction permitting such display, a liquid crystal shutter is disposed in a backlight portion. For displaying a normal liquid crystal screen image, the liquid crystal shutter is used as a diffuser. When a specific image or a display object disposed behind the liquid crystal shutter is displayed in place of an image formed on a liquid crystal display panel, the entire liquid crystal display panel is brought to a transmissive state. At the same time, a voltage is applied to the liquid crystal shutter, which is disposed behind the liquid crystal display panel, in order to bring the liquid crystal shutter to the transmissive state. This makes it possible to discern the display object disposed behind the liquid crystal shutter. In this case, alight source is located on the side of the liquid crystal shutter or the like for fear the discernment of the display object located behind the liquid crystal shutter may be hindered.
The foregoing technology is described in, for example, a patent document 1.
The patent document 1 refers to JP-A-2007-7315.
FIG. 7 is a sectional view of a display device capable of not only displaying an image on a normal liquid crystal display panel but also displaying a fixed image. In the display device shown in FIG. 7, an image formed in a liquid crystal display device is normally displayed. At this time, a liquid crystal shutter 50 disposed behind a liquid crystal display panel is de-energized. In this case, the liquid crystal display shutter 50 works as a diffuser for the liquid crystal display panel.
In the liquid crystal display device shown in FIG. 7, a display object 40 disposed behind the liquid crystal display panel may be displayed. In this case, all the pixels in the liquid crystal display panel are brought to a transmissive state. The liquid crystal shutter 50 is then energized and thus brought to the transmissive state. Since both the liquid crystal display panel and liquid crystal shutter 50 become transmissive, the display object 40 can be discerned from outside the liquid crystal display panel.
As mentioned above, a voltage to be applied to the liquid crystal shutter 50 has to be varied depending on whether an image on the liquid crystal display panel is displayed or the display object 40 is displayed. In order to apply a voltage to the liquid crystal shutter 50, a flexible cable 80 is employed as shown in FIG. 7.
Assembling the components of the display device shown in FIG. 7 is carried out as described below. To begin with, a liquid crystal display panel is disposed in an upper mold 60. Cold-cathode fluorescent lamps (CCFL) 30 and cables 31 for the CCFLs 30 are disposed in a lower mold 65. The cables 31 for the CCFLs 30 are laid to encircle the internal surface of the display device by creating a space on the side of the lower mold 65 behind the CCFLs 30. This brings about a drawback that the contour of the display device gets large.
After the CCFLs 30 and cables 31 are disposed in the lower mold 65, the liquid crystal shutter 50 is placed on the lower mold 65. As mentioned above, a voltage has to be applied in order to energize or de-energize the liquid crystal shutter 50. For the application of the voltage, the flexible cable 80 is employed. The flexible cable 80 is coupled to a printed circuit board (PCB) 75 made of a glass epoxy resin or the like.
The upper mold 60 and lower mold 65 that are formed as mentioned above have to be assembled. In the conventional construction shown in FIG. 7, the flexible cable 80 attached to the liquid crystal shutter 50 is unstable. This poses a problem in that the flexible cable 80 is entangled into the lower mold 65 during assembling, and causes a defective product. Even after the components are assembled as a product, the flexible cable 80 is held unstable. If the product undergoes an impact, there is a fear that such a defect that the flexible cable 80 peels off from the liquid crystal shutter 50 or PCB 75 may take place.
In the related art, the liquid crystal shutter 50 is sandwiched between the upper mold 60 and lower mold 65, and secured by pressing the upper mold 60 against the lower mold 65 using a frame 70. In such a construction, if a completed liquid crystal display device undergoes an impact or the like, the liquid crystal shutter 50 is displaced.